The importance of developmental programming in the beef industry

The beef industry relies on multiple focused segments (e.g., cow-calf, stocker/feeder, and meat packing) to supply the world with beef. Thus, the potential impact of developmental programming on the beef industry needs to be evaluated with regards to the different production traits that drive profitability within each segment. For example, when nutrient restriction of dams occurred early in gestation embryo survival was decreased and the ovarian reserve of heifer progeny was negatively affected. Restriction during mid- to late gestation negatively impacted first service conception rates and pregnancy success of daughters. Even non-nutrient stress has been reported to impact transgenerational embryo development through the male progeny. Primary and secondary muscle fibers form during months two to eight (Days 60-240) of gestation. Therefore, external stimuli (nutrition or environmental) during this window have the potential to decrease the postnatal number of muscle fibers; which has an irreversible impact on animal growth and performance. Nutrient restriction during the last third of gestation resulted in decreased weaning weights, and in some instances decreased dry mater intake, hot carcass weight, and marbling scores. Protein supplementation during late gestation; however, increased weaning weight and ADG to weaning, but progeny of dams restricted in protein in late gestation had greater ribeye area. The importance of developmental programming is recognized; however, its precise application depends on comprehension of its integrated effects across the multiple-focused segments of the beef industry.

Clodronate disodium does not produce measurable effects on bone metabolism in an exercising, juvenile, large animal model

Bisphosphonates are commonly used to treat and prevent bone loss, but their effects in active, juvenile populations are unknown. This study examined the effects of intramuscular clodronate disodium (CLO) on bone turnover, serum bone biomarkers (SBB), bone mineral density (BMD), bone microstructure, biomechanical testing (BT), and cartilage glycosaminoglycan content (GAG) over 165 days. Forty juvenile sheep (253 ± 6 days of age) were divided into four groups: Control (saline), T0 (0.6 mg/kg CLO on day 0), T84 (0.6 mg/kg CLO on day 84), and T0+84 (0.6 mg/kg CLO on days 0 and 84). Sheep were exercised 4 days/week and underwent physical and lameness examinations every 14 days. Blood samples were collected for SBB every 28 days. Microstructure and BMD were calculated from tuber coxae (TC) biopsies (days 84 and 165) and bone healing was assessed by examining the prior biopsy site. BT and GAG were evaluated postmortem. Data, except lameness data, were analyzed using a mixed-effects model; lameness data were analyzed as ordinal data using a cumulative logistic model. CLO did not have any measurable effects on the skeleton of sheep. SBB showed changes over time (p ≤ 0.03), with increases in bone formation and decreases in some bone resorption markers. TC biopsies showed increasing bone volume fraction, trabecular spacing and thickness, and reduced trabecular number on day 165 versus day 84 (p ≤ 0.04). These changes may be attributed to exercise or growth. The absence of a treatment effect may be explained by the lower CLO dose used in large animals compared to humans. Further research is needed to examine whether low doses of bisphosphonates may be used in active juvenile populations for analgesia without evidence of bone changes.

Analysis of nonsynonymous SNPs in candidate genes that influence bovine temperament and evaluation of their effect in Brahman cattle

BACKGROUND

Temperament is an important production trait in cattle and multiple strategies had been developed to generate molecular markers to assist animal selection. As nonsynonymous single nucleotide polymorphisms are markers with the potential to affect gene functions, they could be useful to predict phenotypic effects. Genetic selection of less stress-responsive, temperamental animals is desirable from an economic and welfare point of view.

METHODS AND RESULTS

Two nonsynonymous single nucleotide polymorphisms identified in HTR1B and SLC18A2 candidate genes for temperament were analyzed in silico to determine their effects on protein structure. Those nsSNPs allowing changes in proteins were selected for a temperament association analysis in a Brahman population. Transversion effects on protein structure were evaluated in silico for each amino acid change model, revealing structural changes in the proteins of the HTR1B and SLC18A2 genes. The selected nsSNPs were genotyped in a Brahman population (n = 138), and their genotypic effects on three temperament traits were analyzed: exit velocity, pen score, and temperament score. Only the SNP rs209984404-HTR1B (C/A) showed a significant association (P = 0.0144) with pen score. The heterozygous genotype showed a pen score value 1.17 points lower than that of the homozygous CC genotype.

CONCLUSION

The results showed that in silico analysis could direct the selection of nsSNPs with the potential to change the protein. Non-synonymous single nucleotide polymorphisms causing structural changes and reduced protein stability were identified. Only rs209984404-HTR1B shows that the allele affecting protein stability was associated with the genotype linked to docility in cattle.

Differential Expression of Circadian Clock Genes in the Bovine Neuroendocrine Adrenal System

Knowledge of circadian rhythm clock gene expression outside the suprachiasmatic nucleus is increasing. The purpose of this study was to determine whether expression of circadian clock genes differed within or among the bovine stress axis tissues (e.g., amygdala, hypothalamus, pituitary, adrenal cortex, and adrenal medulla). Tissues were obtained at an abattoir from eight mature nonpregnant Brahman cows that had been maintained in the same pasture and nutritional conditions. Sample tissues were stored in RNase-free sterile cryovials at -80 °C until the total RNA was extracted, quantified, assessed, and sequenced (NovaSeq 6000 system; paired-end 150 bp cycles). The trimmed reads were then mapped to a Bos taurus (B. taurus) reference genome (Umd3.1). Further analysis used the edgeR package. Raw gene count tables were read into RStudio, and low-expression genes were filtered out using the criteria of three minimum reads per gene in at least five samples. Normalization factors were then calculated using the trimmed mean of M values method to produce normalized gene counts within each sample tissue. The normalized gene counts important for a circadian rhythm were analyzed within and between each tissue of the stress axis using the GLM and CORR procedures of the Statistical Analysis System (SAS). The relative expression profiles of circadian clock genes differed (p < 0.01) within each tissue, with neuronal PAS domain protein 2 (NPAS2) having greater expression in the amygdala (p < 0.01) and period circadian regulator (PER1) having greater expression in all other tissues (p < 0.01). The expression among tissues also differed (p < 0.01) for individual circadian clock genes, with circadian locomotor output cycles protein kaput (CLOCK) expression being greater within the adrenal tissues and nuclear receptor subfamily 1 group D member 1 (NR1D1) expression being greater within the other tissues (p < 0.01). Overall, the results indicate that within each tissue, the various circadian clock genes were differentially expressed, in addition to being differentially expressed among the stress tissues of mature Brahman cows. Future use of these findings may assist in improving livestock husbandry and welfare by understanding interactions of the environment, stress responsiveness, and peripheral circadian rhythms.

Telomere Dynamics in Livestock

Telomeres are repeated sequences of nucleotides at the end of chromosomes. They deteriorate across mitotic divisions of a cell. In Homo sapiens this process of lifetime reduction has been shown to correspond with aspects of organismal aging and exposure to stress or other insults. The early impetus to characterize telomere dynamics in livestock related to the concern that aged donor DNA would result in earlier cell senescence and overall aging in cloned animals. Telomere length investigations in dairy cows included breed effects, estimates of additive genetic control (heritability 0.12 to 0.46), and effects of external stressors on telomere degradation across animal life. Evaluation of telomeres with respect to aging has also been conducted in pigs and horses, and there are fewer reports of telomere biology in beef cattle, sheep, and goats. There were minimal associations of telomere length with animal productivity measures. Most, but not all, work in livestock has documented an inverse relationship between peripheral blood cell telomere length and age; that is, a longer telomere length was associated with younger age. Because livestock longevity affects productivity and profitability, the role of tissue-specific telomere attrition in aging may present alternative improvement strategies for genetic improvement while also providing translational biomedical knowledge.

Pharmacokinetics and plasma protein binding of a single dose of clodronate disodium are similar for juvenile sheep and horses

OBJECTIVE

To determine the single-dose pharmacokinetics of clodronate disodium (CLO) in juvenile sheep and the plasma protein binding (PPB) of CLO in juvenile sheep and horses.

ANIMALS

11 juvenile crossbred sheep (252 ± 6 days) for the pharmacokinetic study. Three juvenile crossbred sheep (281 ± 4 days) and 3 juvenile Quarter Horses (599 ± 25 days) for PPB analysis.

METHODS

CLO concentrations were determined using liquid chromatography-mass spectrometry. Pharmacokinetic parameters were calculated by noncompartmental analysis from plasma samples obtained at 0, 0.5, 1, 3, 6, 12, 24, 48, and 72 hours after CLO administered IM at 0.6 mg/kg. PPB was determined using equine and ovine plasma in a single-use rapid equilibrium dialysis system.

RESULTS

The mean and range for maximum plasma concentration (Cmax: 5,596; 2,396-8,613 ng/mL), time of maximal concentration (Tmax: 0.5; 0.5-1.0 h), and area under the curve (AUCall: 12,831; 7,590-17,593 h X ng/mL) were similar to those previously reported in horses. PPB in sheep and horses was moderate to high, with unbound fractions of 26.1 ± 5.1% in sheep and 18.7 ± 7.5% in horses, showing less than a 1.4-fold difference.

CLINICAL RELEVANCE

The pharmacokinetic parameters and PPB of CLO in juvenile sheep were similar to those previously reported in horses. The results suggest that juvenile sheep can be utilized as an animal model for studying the potential risks and/or benefits of bisphosphonate use in juvenile horses.

Comparison of Telomere Length in Age-Matched Primiparous and Multiparous Brahman Cows

Physiological and psychological stressors have been associated with the attrition of telomeres, which are the protective caps of chromosomes. This study compares the telomere length (TL) in 4-year-old Brahman cows grouped by the first parity (n = 8) and the second parity (n = 11). The cows were bled via jugular venipuncture, weighed, and had their body condition scores recorded at Day -28 prior to calving and at Day + 7 and Day + 28 post-calving. The duration of labor (Dlabor) and parturition ease were recorded. The peripheral leukocytes were isolated, the leukocyte blood count with differential was recorded, and the genomic DNA was extracted. The relative quantity of telomere products, which is proportional to the average TL, was determined via multiplex quantitative PCR using the ratio (T/S ratio) of bovine telomere and β-globulin DNA. Standards of the bovine telomere (10¹²-10⁷ dilution series) and β-globulin (10⁹-10⁴ dilution series) genes were utilized to produce relative copy numbers. The samples were assayed in triplicate and were included if the triplicate C_q difference was less than 0.25 cycles. The parity was the fixed effect, and the random effects included the sire and day repeated with the cow as the subject. Statistical significance was not observed in the leukocyte number or type (p > 0.1). A reduction in the TL of approximately 9225 telomeric copies was found between Parity 1 and Parity 2 (p = 0.02). A trend was found between the TL and Dlabor (p = 0.06). The stress of parturition and raising the first calf of a cow's life may be responsible for TL attenuation. Parity may be considered a stressor of cow longevity.

Genetic Variants and Their Putative Effects on microRNA-Seed Sites: Characterization of the 3' Untranslated Region of Genes Associated with Temperament

The 3' untranslated region has an important role in gene regulation through microRNAs, and it has been estimated that microRNAs regulate up to 50% of coding genes in mammals. With the aim of allelic variant identification of 3' untranslated region microRNA seed sites, the 3' untranslated region was searched for seed sites of four temperament-associated genes (CACNG4, EXOC4, NRXN3, and SLC9A4). The microRNA seed sites were predicted in the four genes, and the CACNG4 gene had the greatest number with 12 predictions. To search for variants affecting the predicted microRNA seed sites, the four 3' untranslated regions were re-sequenced in a Brahman cattle population. Eleven single nucleotide polymorphisms were identified in the CACNG4, and eleven in the SLC9A4. Rs522648682:T>G of the CACNG4 gene was located at the predicted seed site for bta-miR-191. Rs522648682:T>G evidenced an association with both exit velocity (p = 0.0054) and temperament score (p = 0.0097). The genotype TT had a lower mean exit velocity (2.93 ± 0.4 m/s) compared with the TG and GG genotypes (3.91 ± 0.46 m/s and 3.67 ± 0.46 m/s, respectively). The allele associated with the temperamental phenotype antagonizes the seed site, disrupting the bta-miR-191 recognition. The G allele of CACNG4-rs522648682 has the potential to influence bovine temperament through a mechanism associated with unspecific recognition of bta-miR-191.

Inter-Individual Variation in DNA Methylation Patterns across Two Tissues and Leukocytes in Mature Brahman Cattle

Quantifying the natural inter-individual variation in DNA methylation patterns is important for identifying its contribution to phenotypic variation, but also for understanding how the environment affects variability, and for incorporation into statistical analyses. The inter-individual variation in DNA methylation patterns in female cattle and the effect that a prenatal stressor has on such variability have yet to be quantified. Thus, the objective of this study was to utilize methylation data from mature Brahman females to quantify the inter-individual variation in DNA methylation. Pregnant Brahman cows were transported for 2 h durations at days 60 ± 5; 80 ± 5; 100 ± 5; 120 ± 5; and 140 ± 5 of gestation. A non-transport group was maintained as a control. Leukocytes, amygdala, and anterior pituitary glands were harvested from eight cows born from the non-transport group (Control) and six from the transport group (PNS) at 5 years of age. The DNA harvested from the anterior pituitary contained the greatest variability in DNA methylation of cytosine-phosphate-guanine (mCpG) sites from both the PNS and Control groups, and the amygdala had the least. Numerous variable mCpG sites were associated with retrotransposable elements and highly repetitive regions of the genome. Some of the genomic features that had high variation in DNA methylation are involved in immune responses, signaling, responses to stimuli, and metabolic processes. The small overlap of highly variable CpG sites and features between tissues and leukocytes supports the role of variable DNA methylation in regulating tissue-specific gene expression. Many of the CpG sites that exhibited high variability in DNA methylation were common between the PNS and Control groups within a tissue, but there was little overlap in genomic features with high variability. The interaction between the prenatal environment and the genome could be responsible for the differences in location of the variable DNA methylation.

PSIII-A-17 Relationships between Diet Quality and Serum Metabolic Indicators in Prenatally Stressed Growing Bos Indicus Heifers

Our research group has previously reported on grazing behavior, diet selection, and weight change in prenatally stressed and translocated Brahman heifers grazing native rangeland. Our current objective was to evaluate relationships between diet quality and metabolic indicators. Twelve yearling heifers were transported ~700 km from Overton, TX to Sonora, TX. Six heifers (283±10 kg) were born to dams subjected to transportation stress during mid-gestation (PNS) and 6 (279±17 kg) were born to non-stressed dams (CON). Heifers grazed a series of 24-ha native range pastures and were sampled (BW, BCS score, blood, and feces) at 2-wk intervals from May through September. Fecal samples collected from the ground or the rectum of each animal were stored at -20o C until processed for near infrared reflectance spectroscopy prediction of diet crude protein (CP) and digestible organic matter (DOM). Blood was obtained via coccygeal venipuncture and processed to yield serum. Serum analyses were obtained from the Texas A&M Veterinary Medical Diagnostic Laboratory. Relationships between constituents of interest were determined by linear regression. Significance was considered to be P &lt; 0.05. Blood urea nitrogen (BUN; mg/dL) was greater (P = 0.04) in PNS (8.39±0.32) than CON (7.39±0.33). Positive correlations were found between CP and BUN (RSQ = 0.76, SE = 1.25 mg/dL; P &lt; 0.001), albumin (RSQ = 0.57, SE = 0.06 mg/dL; P &lt; 0.01), and average daily gain (RSQ = 0.63, SE = 0.47 kg; P &lt; 0.01). Similar relationships were observed between DOM and glucose (RSQ = 0.64, SE = 3.91 mg/dL; P &lt; 0.01), cholesterol (RSQ = 0.37, SE = 5.47 mg/dL; P &lt; 0.05), and average daily gain (RSQ = 0.47, SE = 0.56 kg; P &lt; 0.01). PNS affected circulating nitrogen concentration. Diet quality was related to weight gain and serum indicators of nutritional status.

277 Live Animal Mitochondrial Markers During the Feedlot Phase are Related to Meat Quality in Angus but not Brahman Steers

Mitochondrial activity correlates with meat product quality post-harvest but little is known about the relationships between live animal mitochondria and product quality at slaughter. To test the hypothesis that live animal skeletal muscle mitochondrial markers would be correlated with longissimus Warner-Bratzler shear force (WBSF) post-harvest, longissimus thoracis (LT) and trapezius (TRAP) samples were collected from Brahman and Angus steers (n = 36 per breed) during the grazing growth phase (GP) and after 120 days on feed (FP). Samples were analyzed for mitochondrial enzyme activities via colorimetry and for oxidative phosphorylation (P) and electron transfer (E) capacities via high-resolution respirometry. Relationships between mitochondrial variables and WBSF were determined using PROC CORR in SAS (v9.4). Within Angus in GP, LT mitochondrial volume density as measured by citrate synthase activity (CS) was positively correlated with WBSF (P=0.009). In FP, Angus LT intrinsic (relative to CS) P with complex I (PCI) and maximal E with complexes I and II (ECI+II) were positively correlated with WBSF (P≤0.05), while the contribution of maximal P with complexes I and II (PCI+II) to maximal E (flux control ratio, FCRPCI+II) was negatively correlated with WBSF (P=0.03). Also in FP, Angus TRAP integrative (relative to mg tissue) PCI, PCI+II, and ECI+II and FCRPCI were negatively correlated with WBSF (P≤0.02), while the FCR for electron transfer through complex II only (FCRECII) was positively correlated with WBSF (P=0.007). In Brahman, no mitochondrial markers correlated with WBSF during either GP or FP. Post-harvest meat tenderness is related to live animal skeletal muscle mitochondrial markers when evaluated close to slaughter in Angus but not in Brahman steers.

44 Evaluation of Prenatal Transportation Stress on Humoral and Cell-Mediated Immunity After Modified-Live Viral BVDV Vaccination in Brahman Calves

The objective of this study was to evaluate whether prenatal transportation stress (PNS) affects the immune response of Brahman calves after vaccination against Bovine Viral Diarrhea Virus (BVDV). Mature Brahman cows inseminated to a single Brahman sire in 2018 were assigned to either Control (n=35; not transported) or PNS (n=37; 2h of transportation at 60, 80, 100, 120, and 140±5 d of gestation). Of the calves born in 2019, 11 Control and 12 PNS calves were studied for vaccine treatment (VAX). Temperament score, body weight, and blood samples were obtained from calves prior to weaning (D-28), prior to first BoviShield vaccine (D+35), and after second BoviShield vaccine (D+98). Serum cortisol was determined by RIA. Humoral immune response was evaluated by virus neutralization (VN) assays using serum collected at respective timepoints post-vaccination. Cell-mediated immune (CMI) response was evaluated using a novel PrimeFlow RNA assay that incorporates cell surface marker staining with intracellular RNA expression of cytokines on blood samples obtained at D+35 and D+98. Data were analyzed using GLM procedures of SAS. Only total WBC and absolute lymphocytes were increased with PNS (P&lt; 0.05), while lymphocytes were also decreased with VAX (P&lt; 0.05). There was no PNS effect on the VN or CMI results, serum cortisol concentration, or temperament score. VAX tended (P=0.06) to reduce serum cortisol, as well as resulted in an increase in VN titers (P&lt; 0.01) and frequency of interferon-γ mRNA expression in the CD4+ population (P&lt; 0.01), but not in CD25+ population (P=0.26). Interaction between sampling day and VAX resulted in more drastic increase (P&lt; 0.05) from D+35 to D+98 in VN titers, CD4+ population frequency of interferon-γ mRNA expression, and CD25+ population mean fluorescent intensity. Vaccine treatment positively affected humoral and cell-mediated immune responses; however prenatal transportation stress did not negatively impact response of Brahman calves to immunization against BVDV.

PSIII-A-12 Longissimus Thoracis Mitochondrial Capacities and Temperament of Stocker Calves are Related to Meat Quality at Harvest in Brahman but not in Angus Cattle

Brahman cattle reportedly have decreased meat quality compared to Angus but little is known about the cellular mechanisms driving this difference. We hypothesized that live animal skeletal muscle mitochondria would be related to meat quality. Trapezius and longissimus thoracis (LT) samples were collected from 10-mo-old Angus and Brahman steers designated as calm, intermediate, or temperamental (n=12/group/breed) based on pen score and exit velocity at weaning. Samples were analyzed for citrate synthase (CS) and cytochrome c oxidase (CCO) activities as markers of mitochondrial volume density and function. Calm and temperamental LT samples were also analyzed for oxidative phosphorylation (P) and electron transfer (E) capacities via high-resolution respirometry. At approximately 14.5-mo-old, steers were placed in pens and fed ad libitum. After at least 120 d on feed, animals were harvested and 13th rib LT samples were collected, vacuum packaged, aged 14d, frozen, then subjected to Warner-Bratzler Shear Force (WBSF). Impacts of temperament and breed on WBSF were determined using mixed linear models with breed, temperament, and breed × temperament as fixed effects. Relationships between mitochondrial variables and WBSF were determined using Pearson’s Correlations. Regardless of temperament, WBSF was greater in Brahman than Angus steers (P&lt; 0.0001). Temperament did not impact WBSF in Angus but temperamental Brahman had greater WBSF than both calm and intermediate Brahman (P≤0.01). CS and CCO activities at 10 mo of age were not correlated with WBSF. However, Brahman LT intrinsic (relative to CS) P with complex I (PCI), maximal P with complexes I and II (PCI+II), maximal E with complexes I and II (ECI+II), and E with complex II only (ECII) were positively correlated with WBSF (P≤0.05) while no LT mitochondrial capacity measures correlated with WBSF in Angus. These data may shed light on differences in skeletal muscle energetics leading to decreased meat quality in temperamental Brahman steers.

PSXV-14 Clodronate Use Does not Influence Physical Growth Parameters in Yearling Horses Undergoing Forced Exercise

Off-label bisphosphonate use in juvenile horses is widespread despite little scientific understanding of biological and welfare impacts on skeletally immature, exercising horses. Therefore, the objective was to determine the effects of clodronate disodium on growth parameters of young horses. Thirty-two yearling Quarter horses (335 ± 4 kg, 500 ± 13 d of age) were stratified by age, BW, sex, and initial bone density by aluminum equivalence into four treatment groups for a 168-d trial. The experimental period was divided into two phases mimicking common management practices in horses undergoing sales preparation (Phase I: d 0 to 83) and early performance training (Phase II: d 84 to 168). Horses were housed in individual stalls (3.6 m × 7.2 m). Diets were formulated to meet nutrient requirements including concentrate offered every 12 h and ad libitum access to coastal bermudagrass (Cynodon dactylon) hay and water. Treatments consisted of control (CON; n = 8), single-dose (1X; n = 8), two-dose (2X; n = 8), and four-dose groups (4X; n = 8). All horses received iso-volumetric intramuscular injections of either 1.8 mg/kg BW clodronate disodium (OSPHOSÒ) or saline (placebo) on d 0, 42, 84, and 126. Physical measurements including BW, wither height (WH), hip height (HH), body length (BL), and heart girth (HG) circumference were recorded every 42 d, beginning on d 0. Data were analyzed using PROC MIXED procedure of SAS. There were no treatment differences (P ≥ 0.62) or treatment ′ time interactions (P ≥ 0.25) for BW, WH, HH, BL, and HG, but all measurements increased over time (P ≤ 0.01). These results indicate that clodronate does not impact physical growth parameters in juvenile horses undergoing forced exercise. Further work is ongoing to determine tissue-specific effects of clodronate on bone growth and development in yearling Quarter horses.

DNA methylation patterns and gene expression from amygdala tissue of mature Brahman cows exposed to prenatal stress

Prenatal stress can alter postnatal performance and temperament of cattle. These phenotypic effects may result from changes in gene expression caused by stress-induced epigenetic alterations. Specifically, shifts in gene expression caused by DNA methylation within the brain’s amygdala can result in altered behavior because it regulates fear, stress response and aggression in mammals Thus, the objective of this experiment was to identify DNA methylation and gene expression differences in the amygdala tissue of 5-year-old prenatally stressed (PNS) Brahman cows compared to control cows. Pregnant Brahman cows (n = 48) were transported for 2-h periods at 60 ± 5, 80 ± 5, 100 ± 5, 120 ± 5, and 140 ± 5 days of gestation. A non-transported group (n = 48) were controls (Control). Amygdala tissue was harvested from 6 PNS and 8 Control cows at 5 years of age. Overall methylation of gene body regions, promoter regions, and cytosine-phosphate-guanine (CpG) islands were compared between the two groups. In total, 202 genes, 134 promoter regions, and 133 CpG islands exhibited differential methylation (FDR ≤ 0.15). Following comparison of gene expression in the amygdala between the PNS and Control cows, 2 differentially expressed genes were identified (FDR ≤ 0.15). The minimal differences observed could be the result of natural changes of DNA methylation and gene expression as an animal ages, or because this degree of transportation stress was not severe enough to cause lasting effects on the offspring. A younger age may be a more appropriate time to assess methylation and gene expression differences produced by prenatal stress.

Transfusion of hyperimmune plasma for protecting foals against Rhodococcus equi pneumonia

The bacterium Rhodococcus equi causes pneumonia in foals that is prevalent at breeding farms worldwide. In the absence of an effective vaccine, transfusion of commercial plasma from donor horses hyperimmunised against R. equi is used by many farms to reduce the incidence of pneumonia among foals at farms where the disease is endemic. The effectiveness of hyperimmune plasma for controlling R. equi pneumonia in foals has varied considerably among reports. The purposes of this narrative review are: 1) to review early studies that provided a foundational basis for the practice of transfusion of hyperimmune plasma that is widespread in the US and in many other countries; 2) to summarise current knowledge of hyperimmune plasma for preventing R. equi pneumonia; 3) to provide an interpretive summary of probable explanations for the variable results among studies evaluating the effectiveness of transfusion of hyperimmune plasma for reducing the incidence of R. equi pneumonia; 4) to review mechanisms by which hyperimmune plasma might mediate protection; and 5) to consider risks of transfusing foals with hyperimmune plasma. Although the weight of evidence supports the practice of transfusing foals with hyperimmune plasma to prevent R. equi pneumonia, many important gaps in our knowledge of this topic remain including the volume/dose of hyperimmune plasma to be transfused, the timing(s) of transfusion, and the mechanism(s) by which hyperimmune plasma mediates protection. Transfusing foals with hyperimmune plasma is expensive, labour-intensive, and carries risks for foals; therefore, alternative approaches for passive and active immunisation to prevent R. equi pneumonia are greatly needed. This article is protected by copyright. All rights reserved.

Prenatal transportation stress did not impact ovarian follicle count for three generations of female Brahman offspring

As prenatal transportation stress altered behavior and adrenal glucocorticoid secretion of calves, we hypothesized that prenatal transportation stress would decrease ovarian reserve size and negatively impact female offspring fertility. The impact of prenatal transportation stress on ovarian follicle numbers in female offspring for three generations was studied. Brahman cows were transported for 2 h on day 60 ± 5, 80 ± 5, 100 ± 5, 120 ± 5, and 140 ± 5 of gestation. Ovaries were collected from offspring of transported or non-transported dams at multiple ages. Primordial, primary, secondary, and antral follicles were histologically analyzed. Antral follicle numbers were determined by ultrasound in a subset of offspring. Numbers of primordial, primary, secondary, and antral follicles were analyzed using the MIXED procedure, while the CORR procedure of SAS was used to determine the correlation between follicles observed by ultrasonography and histology. There were no differences (P > 0.05) in the number of primordial, primary, secondary, antral, or total follicles observed histologically due to treatment. Younger females had significantly greater numbers of follicles than older females (P < 0.0001). Antral follicles tended to be correlated with total histological ovarian follicles (P = 0.10). There was no difference in the number of antral follicles observed at ultrasound due to treatment (P = 0.3147), or generation (P = 0.6005) when controlling for age at observation. These results show that short-term transportation stress during early- to mid-gestation did not impact fertility as measured by ovarian follicle numbers in female Brahman offspring for three generations.

25 Temperament and Age Impact Skeletal Muscle Mitochondrial Capacities in Angus Steers

Temperament impacts skeletal muscle mitochondria in Brahman heifers, but this relationship has not been investigated in Angus steers. We hypothesized mitochondrial measures would be greater in temperamental than calm steers, in the trapezius (TRAP) than the longissimus thoracis (LT) muscle, and would increase from 13 to 18 mo of age. Samples from calm (n = 13), intermediate (n = 12), and temperamental (n = 13) Angus steers were evaluated for integrative (per mg tissue) mitochondrial oxidative phosphorylation (P) and electron transfer (E) capacities by high-resolution respirometry. Data were analyzed using linear models with repeated measures (time) and fixed effects of time, muscle, temperament, and all interactions. Leak, P with complex I (PCI), maximal coupled P (PCI+II), maximal noncoupled E (ECI+II), and E with complex II (ECII) decreased from 13- to 18-mo-old (P &lt; 0.0001). Integrative PCI+II, ECI+II, and ECII were greater in the TRAP than LT (P0.005). Leak respiration was greatest in intermediate steers at 13 mo of age (P&lt; 0.0001) but was unaffected by temperament at 18-mo-old. Additionally, ECI+II was greatest in temperamental steers (P0.05) and tended to be greater in intermediate than calm steers (P = 0.1) at 13-mo-old. Overall, PCI, PCI+II, and ECII were greater in temperamental than calm steers (P0.05). ECII was also greater (P = 0.03) and PCI and PCI+II tended to be greater (P0.08) in intermediate than calm steers. The contribution of leak (FCRLeak) and PCI (FCRPCI) to total ECI+II decreased (P &lt; 0.0001) while the contribution of PCI+II (FCRPCI+II) and ECII (FCRECII) to E increased (P0.006) from 13- to 18-mo-old. FCRLeak and FCRPCI were greater (P0.01) and FCRPCI+II tended to be greater (P = 0.08) in the LT than the TRAP. FCRLeak was lowest in temperamental (P0.03) while FCRPCI+II was lowest in calm steers (P0.05). Temperament clearly impacts skeletal muscle mitochondrial capacities and efficiency of energy production in Angus steers, which may be related to product quality at harvest.

79 Prenatally Stressed Brahman Bulls Produced Embryos with Decreased Embryonic Development

The objective of this experiment was to determine if semen collected from prenatally stressed (PNS) Brahman bulls altered early embryonic development compared to control (CON) bulls. Prenatal stress was achieved by transporting Brahman dams for 2h on d60, 80, 100, 120, and 140 (±5d) of gestation. Semen collected from sexually mature male offspring born to transported (PNS; n=4) or non-transported (CON; n = 5) dams was used to fertilize abattoir derived cumulus oocytes complexes (n = 81-100/bull in 2 wells) in an in vitro setting to monitor early embryonic development. Fertilization took place for 18-20h (day 0). Then, putative zygotes were cultured for 8 days. Cleavage was recorded on d3, the number of 1, 2-6, 8-16, or 16-32 cell embryos was recorded on d5, and the number of blastocysts and degenerated embryos was recorded on d8. A subset of blastocysts from PNS (n = 12) or CON (n = 23) bulls were immunolabelled to differentiate inner cell mass (ICM) and trophectoderm (TE). Differences in early embryonic development and ICM:TE ratios were determined using the GLIMMIX procedure in SAS (9.4) with well as a fixed effect. On d3, the percentage of oocytes that cleaved did not differ (P = 0.2660) between treatments. Treatment also had no effect on the percentage of 1 (P = 0.1622), 2-6 (P = 0.1138), 8-16 (P = 0.2722), or 16-32 (P = 0.5586) cell stage embryos on d5 nor the percent of degenerated embryos (P = 0.1130). However, the percentage of embryos that developed to a blastocyst by d8 differed (P = 0.0291) between treatments such that oocytes fertilized by sperm produced by PNS bulls (28%) were less likely to advance to the blastocyst stage compared to CON bulls (35%). The ICM:TE ratio did not differ (P = 0.6484) between treatments. Thus, PNS Brahman bulls do not have an obvious problem to fertilize but may produce sperm with epigenetic modifications that hinder blastocyst formation.

282 Nutritional Monitoring of Prenatally Stressed and Translocated Brahman Heifers

One drought mitigation strategy is transporting livestock to non-drought locations. Our objective was to evaluate the effects of prenatal stress and translocation on growing Bos indicus heifers. Twelve heifers born in spring 2019 at Overton, TX (1245 mm annual precipitation) were transported ~700 km to Sonora, TX (610 mm annual precipitation) in April 2020. Six heifers (283±10 kg) were born to dams subjected to transportation stress during mid-gestation (PNS) and 6 (279±17 kg) were born to non-stressed dams (CON). Heifers grazed a series of 24-ha native range pastures (aboveground forage biomass; 1508±390 kg/ha) and were sampled (non-shrunk BW/BCS score, feces) at 2-wk intervals from May through September. Fecal samples were collected from the ground or the rectum of each animal and stored at -20o C until processed for near infrared spectroscopy (NIRS) and prediction of diet crude protein (CP) and digestible organic matter (DOM). Inputs to a grazing animal nutrition model for prediction of BW included diet CP and DOM, age, and weather. Differences between groups for BW and nutritional parameters were determined by analysis of variance or paired t-test. Both groups gained BW (22±4 kg) throughout the study, there were no differences (P &gt; 0.1) due to treatment. Diet CP and DOM were affected by date (P &lt; 0.01) as diet quality declined from spring to fall. Percent diet CP was greater (P &lt; 0.05) in PNS than CON, especially during July and August (6.94±0.10 vs 6.23±0.17, respectively). Corresponding values for diet DOM were (59.53±0.55 vs 59.14±0.43, respectively; P = 0.09). Observed vs model-predicted weight was different (P &lt; 0.05) for both groups when using CP-based outputs, but not when using metabolizable protein-based outputs (P &gt; 0.1). In summary, PNS heifers selected a diet of greater CP than CON, and tended to select a diet greater in DOM.

245 Prenatal Transportation Stress Does Not Impact Ovarian Follicle Count in Brahman Offspring

Calves from transported dams had greater concentrations of plasma cortisol when restrained and cleared plasma cortisol at a slower rate than calves from non-transported dams. Considering this hypothalamic-pituitary-adrenal axis effect, investigation of other parameters influencing reproduction is warranted in offspring exposed to prenatal transportation stress. The purpose was to determine impact of prenatal transportation stress on offspring ovarian follicle count. Brahman cows were transported for 2 h on d 60, 80, 120, and 140 (± 5 d) of gestation. Offspring from transported (Stressed, n = 19) or non-transported (Control, n = 15) dams were slaughtered at 5 yr (Replication 1, n = 14) or ovariectomized at 8 yr (Replication 2, n = 20). A cross-section of ovary was collected, serially sectioned, and stained. Numbers of total, primordial, primary, secondary, and antral follicles were determined per section. Total ovarian follicle count for each stage was calculated using ovary dimensions. The MIXED procedure of SAS was used to analyze ovarian follicle count with treatment, replicate, and the interaction as fixed effects. Total ovarian follicle count decreased with age (P &lt; 0.01; R1 = 383,663, R2 = 154,560); however, there was no difference in total ovarian follicle count between offspring due to treatment (P = 0.17; S = 221,813, C = 316,409). Similarly, there was no difference in primordial (P = 0.22; S = 127,300, C = 188,304), primary (P = 0.28; S = 58,610, C = 77,237), or antral (P = 0.48; S = 23,202, C = 28,695) follicle count between offspring due to treatment. Fewer secondary follicles were observed in Stressed offspring compared to Control offspring (P = 0.03). These results suggest that the ovarian follicular reserve, AFC, and potential fertility of cows may not be impacted by exposure to prenatal transportation stress. USDA is an equal opportunity provider and employer.

241 Skeletal Muscle Mitochondrial Capacities Are Impacted by Breed and Temperament in Young Angus and Brahman Steers

Temperament impacts skeletal muscle mitochondria in Brahman heifers, but this has not been investigated in steers or between cattle breeds. We hypothesized mitochondrial measures would be greater in Angus than Brahman, temperamental than calm steers, and the trapezius (TRAP) than the longissimus thoracis (LT) muscle. Samples from calm (n = 13 per breed), intermediate (n = 12 per breed), and temperamental (n=13 per breed) Angus and Brahman steers (mean±SD 10.0±0.8 mo) were evaluated for mitochondrial enzyme activities via colorimetry. Calm and temperamental LT samples were evaluated for oxidative phosphorylation (P) and electron transfer (E) capacities by high-resolution respirometry. Data were analyzed using linear models with fixed effects of breed, muscle, temperament, and all interactions. Brahman tended to have greater mitochondrial volume density (citrate synthase activity; CS) than Angus (P = 0.08), while intrinsic (relative to CS) mitochondrial function (cytochrome c oxidase activity) was greater in Angus than Brahman (P = 0.001) and greater in TRAP than LT (P = 0.008). Angus exhibited greater integrative (per mg tissue) and intrinsic P with complex I (PCI), P with complexes I+II (PCI+II), maximum noncoupled E, and E with complex II (ECII; P ≤ 0.04) and tended to have greater intrinsic leak (P = 0.1) than Brahman. Contribution of PCI to total E was greater in Angus than Brahman (P = 0.01), while contribution of ECII to total E was greater in Brahman than Angus (P = 0.05). A trend for the interaction of breed and temperament (P = 0.07) indicated calm Angus had the greatest intrinsic ECII (P ≤ 0.03) while intrinsic ECII was similar between temperamental Angus and calm and temperamental Brahman. Integrative PCI+II and ECII, and the contribution of PCI and PCI+II to overall E tended to be greater in temperamental than calm steers (P ≤ 0.09), while intrinsic ECII tended to be greater in calm than temperamental steers (P = 0.07). The impact of these mitochondrial differences on meat quality measures remains to be determined.

Hyperalgesia after a Drinking Episode in Young Adult Binge Drinkers: A Cross-Sectional Study

AIMS

Rodent studies propose potential mechanisms linking excessive drinking and pain hypersensitivity (hyperalgesia), such that stress hormones (i.e. epinephrine and cortisol) mediate induction and maintenance of alcohol withdrawal-induced hyperalgesia. The first aim of this study was to examine whether hyperalgesia would occur within 48 h after a drinking episode in healthy young adult binge drinkers. The second was to examine whether stress hormones and negative effect would be associated with binge drinking or alcohol withdrawal-associated hyperalgesia.

METHODS

A cross-sectional experiment was conducted in five groups with naturally occurring drinking (mean age = 19.6, range 18-29 years): abstainers (n = 43, 54% female), moderate drinkers with (n = 50, 50% female) or without recent drinking (i.e. within 48 h, n = 23, 26% female) and binge drinkers with (n = 36, 58% female) or without recent drinking (n = 25, 44% female). All types of drinkers endorsed drinking about 2-3 times a month and 2-3 years of drinking history.

RESULTS

Muscle pressure pain thresholds were significantly lower in the binge group with recent drinking compared to other groups, but cutaneous mechanical and heat pain thresholds were not significantly different across the five groups. Basal epinephrine levels were significantly higher in binge groups regardless of recent drinking, but cortisol and negative effect were not significantly different across the five groups.

CONCLUSIONS

This is the first study to show that alcohol withdrawal-associated muscle hyperalgesia may occur in healthy episodic binge drinkers with only 2-3 years of drinking history, and epinephrine may play a role in binge drinking-associated hyperalgesia.

Evaluation of Prenatal Transportation Stress on the Number of Pituitary Corticotrophs in Mature Brahman Cows

Prenatal transportation stress (PNS) results in calves that are more temperamental and have greater circulating concentrations of cortisol compared to control calves. The objective of this experiment was to evaluate whether PNS alters the number of pituitary corticotrophs in mature Brahman cows. We hypothesized that the increased circulating cortisol concentrations previously characterized in this bovine model is associated with developmental changes in the anterior pituitary leading to an increased number of corticotrophs. Pregnant Brahman cows (n = 48) were transported in trailers for 2-hour periods at 60±5, 80±5, 100±5, 120±5, and 140±5 days of gestation. Non-transported pregnant cows (n = 48) were designated as the Control group. Control and PNS offspring heifers were managed together under the same environmental conditions. At approximately 5 yr of age, randomly selected non-pregnant cows (Control, n = 8; PNS, n = 6) were humanely harvested and the whole pituitaries were collected. Pituitaries were weighed, fixed in paraformaldehyde, serially dehydrated with graded ethanol, embedded in paraffin blocks, and cut into 5-μm sections. Immunohistochemistry was performed to detect cells expressing adrenocorticotropic hormone (ACTH) as a marker for corticotrophs. Three comparable sections from the midsagittal plane from each animal were processed using an ovine ACTH-specific antibody (Dr. A.F. Parlow, NIDDK). Five fields of view were analyzed per section (15 fields per animal). Anterior pituitary gland weight did not differ (P &gt; 0.10) between groups (Control = 2.11 ± 0.12 g; PNS = 2.10 ± 0.15 g). The mean number of ACTH-positive cells between control (531±56 cells/section) and PNS cows (477±49 cells/section) also did not differ (P &gt; 0.10). In conclusion, the number of pituitary corticotrophs in mature Brahman cows was not affected by prenatal transportation stress and is likely not a mechanism mediating the increased circulating cortisol concentrations seen in this bovine model of fetal programming.

Evaluation of Peripheral Blood Leukocytes as a Surrogate for RNA-Seq Detection of Gene Expression in Stress Axis Tissues of Mature Brahman Cows

Longitudinal studies of gene expression where sampling certain organ systems is precluded may become more feasible if a more accessible, representative biological sample could be identified. The objective of this study was to determine whether peripheral blood leukocytes (PBL) could be an effective surrogate for assessing gene expression differences within neuroendocrine tissues that regulate stress responses. Specifically, leukocyte samples and stress axis tissues, including the paraventricular region of the hypothalamus, anterior pituitary gland, adrenal cortex, and adrenal medulla were isolated from humanely slaughtered 5-yr-old Brahman cows (n = 8). RNA was extracted from each sample and gene expressions were calculated using bioinformatic approaches of RNA-Seq analysis. Differentially expressed genes (DEG) between adrenal axis tissue RNA and PBL RNA were identified using the edgeR Package from Bioconductor, R. More than 3,000 DEGs were identified in each tissue relative to the PBLs. Overall, higher gene expression levels were observed in the hypothalamus vs PBL, while the remaining tissues had reduced expression compared to PBL (Table 1). Pearson correlation values were calculated from the mean normalized gene count in the PBL and tissues for genes (n = 17) important for stress response and metabolism to assess PBL as a possible surrogate for gene expression analyses (Table 2). Only two genes, oxytocin and 11β-hydroxylase, were positively correlated (P &lt; 0.05) between PBL and specific tissue gene expression. As typically observed among different cell types, gene expression differences exist between the PBL and various tissues of the HPA axis. Therefore, it remains to be determined if gene expression in the surrogate PBL will shift in a direction similar to that of specific adrenal axis tissue of mature Brahman cows exposed to stressors during key developmental periods.

The Potential Use of DNA Methylation Patterns from Peripheral Blood Leukocytes as a Surrogate for Stress Axis Tissues in Mature Brahman Cows

DNA methylation (DNAm) patterns are tissue specific and aid in tissue specific gene expression changes. The use of DNAm patterns from peripheral blood leukocytes (PBL) as a surrogate for patterns in other tissues is common, especially in longitudinal studies when sampling of tissues is not plausible. Thus, the objective of this study was to investigate the suitability of using DNAm patterns of PBL as a surrogate for the DNAm patterns in neuroendocrine tissues responsible for stress responses and energy metabolism. Samples from the paraventricular region of the hypothalamus, anterior pituitary gland, adrenal cortex, and the adrenal medulla were harvested from 5-yr-old Brahman cows (n = 8) and DNA was extracted from each sample. Methylation was assessed using reduced representation sodium bisulfite sequencing and differentially methylated regions (DMR) between the PBL DNA and tissue DNA were identified using EdgeR from Bioconductor, R. Analysis revealed over 15,000 DMRs located within promoter regions of genes in each tissue, with the majority of the sites having increased methylation in the PBL (Table 1). To further evaluate the use of PBL DNA as a surrogate, Pearson correlation values were calculated for genes (n = 20) pertinent to each respective tissue using the mean methylation of the specific gene in the PBL and in the tissue (Table 2). Three correlations were significant (P ≤ 0.05), two of which were negative. The sizable differences indicate that DNA methylation patterns from PBL do not compare well to patterns from hypothalamic, pituitary, adrenal cortex, and adrenal medulla tissues from 5-yr-old Brahman cows. This is especially the case for the majority of the specific genes examined in this study. Whether DNAm in the surrogate PBL will shift in a direction similar to that of specific tissues of Brahman cows exposed to stressful stimuli during developmental periods remains to be determined.

Differential Expression of Circadian Clock Genes in the Bovine Neuroendocrine Adrenal System

The primary objective of this investigation was to determine whether circadian clock genes were differentially expressed within or among bovine hypothalamic paraventricular nucleus (PVN), anterior pituitary gland (AP), adrenocortical (AC) and adrenomedullary (AM) tissues. The PVN, AP, AC, and AM were isolated from 5-yr-old Brahman cows (n = 8) harvested humanely at an abattoir between 0800-1100 h. Expression of target genes in each sample was evaluated via RNA-sequencing analyses. Gene counts were normalized using the trimmed mean of M values (TMM) method in the edgeR Package from Bioconductor, R. The normalized gene counts of genes important for circadian rhythm were statistically analyzed using the GLM Procedure of SAS. The genes analyzed were circadian locomotor output cycles protein kaput (CLOCK), cryptochrome circadian regulator 1 and 2 (CRY1 and CRY2), aryl hydrocarbon receptor nuclear translocator like (ARNTL), period circadian regulator 1 and 2 (PER1 and PER2), neuronal PAS domain protein 2 (NPAS2), and nuclear receptor subfamily 1 group D member 1 (NR1D1). Overall, relative expression profiles of clock genes differed (P &lt; 0.01) within each tissue with PER1 having greater expression in all tissues (P &lt; 0.01). Within the PVN expression of CLOCK, CRY1, ARNTL, and PER2 was less than that of CRY2, NPAS2, and NR1D1 (P &lt; 0.01). In the AP, with the exception of PER1, no other clock gene differed in degree of expression. In the AC, expression of CLOCK and NPAS2 was greater than CRY1, ARNTL, PER2, and NR1D1 (P &lt; 0.05), whereas CRY2 expression exceeded only CRY1 (P &lt; 0.05). Within the AM, CLOCK and CRY2 expression was greater than CRY1 and ARNTL (P &lt; 0.05). Overall, clock gene expression among tissues differed (P &lt; 0.01) for each individual clock gene. The AC and AM had similar clock gene expression, except expression of CRY2 and PER2 was greater in AM (P &lt; 0.05). The AC and AM had greater expression of CLOCK than the PVN and AP (P &lt; 0.01), with PVN having greater expression than AP (P &lt; 0.01). The AP had greater expression of NPAS2, followed by PVN, with the least expression in the AC and AM (P &lt; 0.01). Both PVN and AP had greater CRY1 and NR1D1 expression than AC or AM (P &lt; 0.01). The AP had greater PER1 expression than PVN, AC, and AM (P &lt; 0.01), whereas PVN, AC, and AM had greater ARNTL expression than AP (P &lt; 0.05). Both AP and AM had greater expression of PER2 than PVN or AC (P &lt; 0.01). The PVN had greater expression of CRY2 than the AP, AC, and AM (P &lt; 0.01). These results indicated that within each tissue the various clock genes were expressed in different quantities. Also, the clock genes were expressed differentially among the tissues of the bovine neuroendocrine adrenal system. Temporal relationships of these genes with the primary endocrine products of these tissues should be investigated to define the roles of peripheral clock genes in regulation of metabolism and health.

Evaluation of the effects of sire and dam calving group on age at first calving in Brahman heifers

This study evaluated the possible effects of sire and dam calving groups on age at first calving in Brahman heifers. A total of 570 heifers born between the years 2004 and 2017 were exposed as yearlings to fertile bulls through time of pregnancy determination. A calving group was determined by calculating the mean (993 d) and standard deviation (187 d) of heifer age at first calving. Heifers considered to calve early (≤899 d; calving group = 1) or late (≥1087 d; calving group = 3) were at least half a standard deviation (94 d) away from the mean. All other heifers were considered to have an intermediate age at first calving (900-1086 d; calving group = 2). Of the 570 heifers, only heifers from a dam (n = 182) with a known age at first calving and from a sire (n = 35) with 5 or more daughters were kept to determine the effect of dam calving group and the effect of sire calving group on age at first calving and calving group in daughters, resulting in a total of 284 heifers available for analysis. Variables included were dam and sire calving groups of the heifer, heifer age at first calving, heifer calving group, heifer season of birth, and heifer year of birth. Data were analyzed using the GLM procedures of SAS and proportions were tested using Chi-square. Sire calving group did affect (P < 0.01) age at first calving and calving group in heifers, but dam calving group did not affect (P > 0.10) daughter age at first calving or calving group. Analysis of dam calving group and sire calving group effects identified a year of birth effect (P < 0.01) on daughter age at first calving and calving group, whereas there was no significant season of birth effect. The proportion of daughters calving early for sire calving groups differed significantly from the expected proportion (P < 0.01), whereas the proportion of daughters calving early for dam calving groups did not differ. An effort to produce a greater proportion of Brahman heifers capable of calving early will not be effective from the dam side but may be effective from the sire side.

Effect of bioactive proteins on gait kinematics and systemic inflammatory markers in mature horses

Twenty-seven mature Quarter horses were used in a randomized design to determine the effects of bioactive protein supplementation on gait kinematics and systemic inflammatory markers in a 34-d trial. Treatments consisted of oral doses of 230 g/d of pelleted supplements containing 0 g (CON; n = 9), 40 g of bioactive protein (40BP; n = 9; LIFELINE, APC, LLC, Ankeny, IA), and 80 g of bioactive protein (80BP; n = 9) daily. Horses were fed a commercial concentrate at 0.5% BW (as-fed) and received ad libitum coastal bermudagrass (Cynodon dactylon) hay daily. On day 33, horses consistent in exercise (CON, n = 6; 40BP, n = 8; 80BP, n = 7) participated in a trailering and riding challenge. Kinematic gait analysis was performed on day 0 for use as a covariate, and on day 14, 28, and 34 to allow for the determination of potential time and dosage effects. Video footage was collected and analyzed using gait analysis software (EquineTec, Monroe, GA) for the determination of stride length (SL) and range of motion (ROM). Blood was collected via jugular venipuncture on days 0, 14, 28, and 34 for determination of systemic expression of tumor necrosis factor (TNF)-α and IL-1β. Data were analyzed using PROC MIXED of SAS. A trend towards treatment × time interaction was observed in ROM of the knee at the walk (P = 0.10), due to the increasing ROM for 40BP and 80BP as time increased and decreasing ROM for CON. A treatment × time interaction was observed (P < 0.01) for hock ROM at a walk resulting from CON and 80BP decreasing from day 14 to 28 with 40BP increasing, while from day 28 to 34 ROM at a walk decreased for 40BP and increased for 80BP. The main effect of treatment on hock ROM at the walk was quadratic (P < 0.01) and characterized by higher ROM values for 40BP compared to CON or 80BP. Dietary treatment lengthened (P = 0.04) SL of the hind limb at the walk for 40BP and 80BP compared to CON on both days 14 and 28. A significant treatment × time interaction was observed in the expression of IL-1β (P < 0.01) and can be explained by lower concentrations of IL-1β for 80BP on day 34 compared to the other treatments, with 40BP being intermediate and CON being the highest. Increased articular ROM with decreased expression of IL-1β may indicate potential anti-inflammatory effects of 80 g/d of bioactive proteins.

26 Evaluation of sire versus dam effect on age at first calving in Brahman heifers

This study evaluated the possible effects of sire and dam on age at first calving in Brahman heifers. A total of 570 heifers born between the years 2001 and 2017 were exposed as yearlings to fertile bulls through time of pregnancy determination. A calving code was determined by calculating the mean (993 d) and standard deviation (187 d) of heifer age at first calving. Heifers considered to calve early (≤899 d; calving code = 1) or late (≥1087 d; calving code = 3) were at least half a standard deviation (94 d) away from the mean. All other heifers were considered to have a normal age at first calving (900 to 1086 d; calving code = 2). There were 35 sires with 5 or more daughters, resulting in a total of 543 heifers evaluated for the effect of sire. There were 323 daughters of evaluated heifers, which were evaluated for the effect of dam calving code. Also evaluated was the effect of dam and sire calving code on age at first calving of female offspring (n = 287). Variables analyzed included dam and sire of the heifer, age at first calving, and calving code. Data were analyzed using the GLM procedures of SAS and proportions were tested using Chi-square. Sire calving code did affect (P &lt; 0.01) age at first calving and calving code in heifers, but dam calving code did not affect daughter calving code and age at first calving (Table 1). The proportion of daughters calving early compared to sire calving code significantly differed from the expected proportions (P &lt; 0.01), whereas the proportions of daughters calving early for dam calving code did not differ (Table 2). A selection effort to produce Brahman heifers capable of calving early will not be effective from the dam side, but can be effective on the sire side.

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157 Spectroscopic analysis of tissues collected from male goats differing in genetic propensity to consume juniper

Juniper (Juniperus spp.) foliage is consumed by free-ranging goats in the southwestern US. Junipers contain monoterpenes which have toxicological and pharmacological effects. We sampled 20 male Spanish goats (Capra hircus; 10 young [2-year-old] and 10 old [3-5-year-old]) from a herd selected for their propensity to consume a high (estimated breeding value [EBV] = 13.01 ± 0.20) or low (EBV = -14.76 ± 0.48) proportion of juniper in the diet to determine the ability of near infrared spectroscopy (NIRS) in detecting physico-chemical differences in animal tissues. Heart (ventricle; interior and exterior surfaces), liver (caudate lobe), and muscle (longissimus dorsi) samples as well as an entire kidney and testicle, were collected at harvest (n = 5 of each age [i.e. length of exposure to monoterpenes] and juniper EBV combination). Tissue samples were stored in whirl-pac bags at -20o C and later thawed to ~24o C for NIRS analysis. Spectra (400–2500 nm) were obtained with an ASD Field Spec using a contact probe directly through the whirl-pac sample bag. Principal component and partial least squares regression procedures were accomplished in SAS; P &lt; 0.05 indicated statistical significance. Both age (RSQ, 0.2 to 0.6; P &lt; 0.05) and juniper EBV (RSQ, 0.2 to 0.65; P &lt; 0.05) were correlated with near infrared (NIR) spectral characteristics. Propensity to consume juniper was most strongly correlated with NIR spectra in testicular tissue (RSQ = 0.65, MSE = 0.25, P &lt; 0.01), and least strongly correlated in the heart interior surface (RSQ = 0.21, MSE = 0.21, P &lt; 0.05). Spectral correlations with propensity to consume juniper were stronger in tissues from old (RSQ ~ 0.68) than young (RSQ ~ 0.52) goats, especially in liver, kidney, muscle, and testicle. Physico-chemical differences in goat tissues were affected by genetic propensity to consume juniper, and these were detected by NIRS.

PSII-25 Detection of neurotransmitter-related molecules by untargeted metabolomic analysis of rumen fluid from monensin-treated temperate and tropically adapted beef cattle

The effect of an ionophore on the ruminal metabolome of temperate and tropically-adapted cattle was evaluated. For 21 d, five Angus, 5 Brahman, and 5 BrahmanXAngus F1 steers (264 kg BW) with 5 steers per pen within breedtype, were fed Tifton bermudagrass hay ad libitum, at the conclusion of which rumen fluid (100-to-250 mL) was collected and stored at -80°C (PRE). During a subsequent 21-d period, all steers were fed Tifton hay ad libitum plus a supplement (908 g corn, 217 g soybean meal, 60 g dried molasses) with monensin (220 mg·steer−1·d−1) individually, at the conclusion of which rumen fluid (100-to-250 mL) was collected and stored at -80°C (POST). Rumen fluid samples were processed for an untargeted analysis by LC/MS on Compound Discoverer v.3.1. Approximately 2,043 compounds were detected with 825 being annotated by ChemSpider and other databases, of which several were associated with four neurotransmitters; acetylcholine (ACh), dopamine, γ-aminobutyric acid (GABA), and serotonin. After monensin, several ACh-related molecules increased (P &lt; 0.003) in Angus (POST:PRE ratio=7.906) but ACh decreased (P &lt; 0.043) in the F1 (ratio= 0.391) steers. Dopamine and dopamine-related molecules decreased (P &lt; 0.01) in Angus (ratio= 0.149) and F1 steers (ratio= 0.206) after monensin. No changes for rumen presence of ACh or dopamine occurred in Brahman steers after monensin. Multiple molecules related to GABA increased in Angus (P &lt; 0.03) and Brahman (P &lt; 0.02) steers. Serotonin-related molecules such as the metabolite 5-hydroxyindoleacetic acid (5-HIAA; ratio= 4.389) increased (P &lt; 0.005) only in Brahman steers. The addition of monensin to the diet differentially altered the presence of neurotransmitter-related molecules in the rumen fluid of temperate and tropically adapted beef cattle. Further research regarding physiological roles of ruminal neurotransmitters and modulation by ionophores that affect ruminal microbiota is warranted. Support: USDA FAH

145 President Oral Presentation Pick: Prenatal stress increases skeletal muscle mitochondrial volume density and function in yearling Brahman calves

We previously determined that prenatal stress (PNS) differentially affected methylation of DNA from leukocytes of 28-d-old calves. Specifically, COX14 (cytochrome c oxidase (COX) assembly factor) and CKMT1B (mitochondrial creatine kinase U-type) were hypomethylated and COA5 (COX assembly factor 5), COX5A (COX subunit 5A), NRF1 (nuclear respiratory factor 1), and GSST1 (glutathione S-transferase theta-1) were hypermethylated in PNS compared to non-PNS calves (P ≤ 0.05). Our current objective was to test the hypothesis that PNS exhibit impaired mitochondrial function and greater oxidative stress than non-PNS calves. Blood and longissimus dorsi muscle samples were collected from yearling Brahman calves whose mothers were stressed by 2 h transportation at 60, 80, 100, 120, and 140 days of gestation (PNS; 8 bulls, 6 heifers) and non-PNS calves (4 bulls, 6 heifers). Serum was evaluated for the stress hormone, cortisol, and muscle damage marker, creatine kinase; muscle was analyzed for mitochondrial volume density and function by citrate synthase (CS) and COX activities, respectively, concentration of malondialdehyde, a lipid peroxidation marker, and activity of the antioxidant, superoxide dismutase (SOD). Data were analyzed using mixed linear models with treatment and sex as fixed effects. Serum cortisol was numerically higher in PNS than non-PNS calves but was not statistically different. Muscle CS and COX activities relative to protein were greater in PNS than non-PNS calves (P ≤ 0.03), but COX relative to CS activity was similar between groups. Activity of COX was greater in bulls than heifers (P = 0.03), but no other measure was affected by sex. All other measures were unaffected by PNS. Prenatal stress did not affect markers of muscle damage and oxidative stress in yearling Brahman calves at rest but mitochondrial volume density and function were greater in PNS calves. Acute stressors induce oxidative stress, so implications of differences in mitochondria in PNS calves following a stressor should be investigated.

109 Metabolic and endocrine indicators in male goats differing in genetic propensity to consume juniper

We sampled Spanish goats selected for their propensity to consume above (H) or below (L) the population average for proportion of juniper/monoterpenes in the diet (as determined by fecal near infrared spectroscopy) to determine the effect of juniper/monoterpenes on metabolic/endocrine indicators in adult male goats (Y: 2-year-old and O: 3-5-year-old). Body weight (kg) and serum samples were collected from 20 animals [n = 5 of each age (i.e. length of exposure to monoterpenes) and juniper consumption combination] maintained solely on pastures inhabited by juniper. Differences in serum analytes between groups were determined by analysis of variance. Body weight was not different between juniper groups (~71.1 ± 3.4 each) but was greater in O (76.0 ± 3.7) than Y (66.3 ± 1.9). Glucose (mg/dL) was numerically higher (P = 0.15) in H (82.3 ± 7.3) than L (69.5 ± 3.8) and in O (81.9 ± 1.9) than Y (69.9 ± 2.3). Serum urea nitrogen (mg/dL) was 10.5 ± 1.0 in both H and L (P &gt; 0.1) but was significantly higher (P &lt; 0.004) in O (12.9 ± 1.3) compared to Y (8.2 ± 0.5). NEFA (mEq/L) was significantly higher (P &lt; 0.02) in H (0.33 ± 0.04) than L (0.26 ± 0.02), but not in O (0.30 ± 0.04) versus Y (0.29 ± 0.03). Total globulin (g/dL) was significantly higher (P &lt; 0.007) in L (4.34 ± 0.35) than H (3.40 ± 0.16), and in O (4.29 ± 0.38) than Y (3.45 ± 0.12). Gamma glutamyl transferase was significantly higher (P &lt; 0.0001) in H (59.2 ± 2.1) than L (44.3 ± 2.2), and in Y (55.3 ± 2.9) than O (48.2 ± 3.2). Length of exposure (via advancing age) and preference for juniper may incur a cost of fitness in goats selected for higher than average consumption of monoterpenes.

132 Proportional tissue weights in male goats differing in genetic propensity to consume juniper

Metabolic and endocrine tissues of goats (Capra hircus) consuming juniperus species containing monoterpenes were evaluated. Monoterpenes have toxicological and pharmacological effects. We sampled Spanish goats selected for their propensity to consume above (H) or below (L) the population average for proportion of juniper in the diet as determined by fecal near infrared spectroscopy. Our objective was to determine the effect of divergent propensity to consume juniper on various tissues in adult male goats [young (2-year-old) and old (3-5-year-old)] grazing pastures containing juniper at the Texas A&M AgriLife Sonora Research Station. In June 2019, 20 animals (n = 5 of each age and juniper consumption combination) were slaughtered at the Angelo State University Meats Lab. Body weight was recorded 2 days prior to harvest. Tissue samples (i.e. liver, kidney, heart, adrenal, testicle, epididymis) were collected and weighed at the time of harvest. Tissue weights were analyzed as a proportion of body weight. Differences in proportional tissue weights between young (Y) and old (O), H and L animals were determined by analysis of variance. Body weights (kg) were 75.5 ± 4.2, 76.5 ± 6.2, 63.5 ± 1.9, and 69.0 ± 2.8 for HO, LO, HY and LY respectively. Body weight for O (76.0 ± 3.72) was greater (P &lt; 0.03) than Y (66.3 ± 1.9). Total paired testicle, epididymal, adrenal, and heart proportional weight (g/kg) was not affected (P &gt; 0.1) by age nor juniper consumption group. Total paired proportional weight was significantly greater (P &lt; 0.05) in H (2.53 ± 0.09) than L (2.19 ± 0.08) for kidneys and greater (P = 0.15) in H (15.80 ± 0.75) than L (14.58 ± 0.39) for liver. High apparent consumption of juniper was associated with an increase in mass of tissues typically involved in metabolism, biotransformation, and elimination of plant secondary compounds.

35 Differential haptoglobin responsiveness to a Mannheimia haemolytica challenge altered immunologic, physiologic, and behavioral responses in beef steers

A retrospective analysis of data from a previous study (Kayser et al., J. Anim. Sci. 97:596; 2019) revealed that steers challenged with Mannheimia haemolytica (MH) had divergent serum haptoglobin (HPT) despite having similar leukocyte and temperature responses. In that study, 36 steers (BW 352 ± 23 kg) were fitted with rumen boluses and were fed from electronic bunks to measure DMI and feeding behavior prior to inoculation with saline or MH. Whole blood was collected on days -4, 0, 1, 2, 3, 5, 7, 10 and 14 relative to MH inoculation. The MH steers were retrospectively classified as HPT responsive (RES; n = 9; mean AUC = 62.6 mg/dL/d) or HPT non-responsive (NON; n = 9; mean AUC = 4.5 mg/dL/d). The current objective was to determine if the HPT responsive phenotype altered other immunologic, physiologic, or behavioral responses, compared to saline controls (CON; n = 18). The magnitude of increase in neutrophils (P&lt; 0.01) and total leukocytes (P&lt; 0.05) was greater in RES than NON or CON on day 1. All MH-challenged steers experienced a transient febrile response, but temperature was greater (P&lt; 0.01) in RES on days 0 and 4 compared to NON and CON. Intake was depressed in all three groups d 0, but magnitude of depression in RES was greater (P&lt; 0.01) than NON or CON, and remained lower (P&lt; 0.01) d 1, 2, 3, 6, and 8. Bunk-visit duration was decreased (P&lt; 0.01) in all MH-challenged steers on day 0, but RES were greater (P&lt; 0.02) than NON and CON d 11 and 12. Correspondingly, bunk-visit eating rate of RES was decreased (P&lt; 0.01) from day 2 - 14. Had this not been a sub-clinical challenge model, the greater reduction in intake and increased leukocyte recruitment may have resulted in performance differences between RES and NON steers. These results suggest that differences in HPT responsiveness may be associated with differences in innate immunocompetence.

86 Evaluation of the effect of prenatal transportation stress on endocrine and immune tissues of neonatal Brahman calves

The objective of this experiment was to evaluate whether prenatal transportation stress (PNS) affects the weight of endocrine and immune tissues of calves. Mature Brahman cows inseminated to a single Brahman sire in 2018 were assigned to be either Control (n = 35; not transported) or PNS (n = 37; 2 h of transportation at 60, 80, 100, 120, and 140 ± 5 d of gestation). Of the calves born in 2019, 16 Control (8 bulls and 8 heifers) and 16 PNS (8 bulls and 8 heifers) calves were studied. Pen score, body weight, and blood samples were obtained from calves at 25 ± 2 d of age. At that time, calves were euthanized by barbiturate overdose in order to collect tissues (brain, pituitary and adrenal glands, spleen and thymus). Tissues were trimmed and weighed. Serum cortisol was determined by RIA. Data were analyzed using ANOVA, GLM, and CORR procedures of SAS with body weight at sample collection as a covariate. Whole pituitary weight tended (P = 0.08) to be greater in females compared to males, whereas anterior pituitary weight tended (P = 0.06) to be greater in PNS. Whole brain weight was greater (P &lt; 0.01) in males. The interaction of treatment and sex on whole brain weight of PNS tended (P = 0.09) to fall between that of the Control females and Control males. Whole pituitary weight was positively correlated with total adrenal weight (r = 0.32; P = 0.08). Total thymus weight positively correlated with whole brain and total adrenal weight (r = 0.43 and 0.41, respectively; P &lt; 0.05). Serum cortisol was negatively correlated with spleen weight and total immune tissue weight (r = -0.37 and -0.38, respectively; P &lt; 0.05). Results suggest next steps should include a closer look at function of immune tissues by studying PNS effect on thymus response to immunization.

Temperament influences mitochondrial capacity in skeletal muscle from 8 through 18 mo of age in Brahman heifers

Temperamental cattle tend to yield carcasses of poorer quality, and Brahman cattle are reportedly more temperamental than non-indicus cattle breeds. A potential link between temperament and product quality may be mitochondrial activity. We hypothesized that mitochondrial measures would be greater in temperamental compared with calm heifers and that the relationships between temperament and mitochondria would persist as heifers age. Serum cortisol and skeletal muscle (longissimus thoracis [LT] and trapezius [TRAP]) mitochondrial profiles and antioxidant activities were quantified from the same calm (n = 6) and temperamental (n = 6) Brahman heifers at 8, 12, and 18 mo of age. Data were analyzed using a mixed model ANOVA in SAS (9.4) with repeated measures. Serum cortisol was greater in temperamental compared with calm heifers throughout the study (P = 0.02). Mitochondrial volume density (citrate synthase [CS] activity) increased over time (P < 0.0001) but was similar between temperament and muscle groups. Mitochondrial function (cytochrome c oxidase activity) was greatest in the temperamental LT at 8 mo of age (P ≤ 0.0006), greatest in the temperamental TRAP at 18 mo of age (P ≤ 0.003), and did not differ by temperament at 12 mo of age. Integrative (relative to tissue wet weight) mitochondrial oxidative phosphorylation capacity with complex I substrates (PCI), PCI plus complex II substrate (PCI+II), noncoupled electron transfer system capacity (ECI+II), and E with functional complex II only (ECII) were greater in the TRAP than LT for calm heifers at all ages (P ≤ 0.002), but were similar between muscle groups in temperamental heifers. Overall, calm heifers tended to have greater intrinsic (relative to CS activity) PCI and flux control of PCI+II (P ≤ 0.1) than temperamental heifers, indicating greater utilization of complex I paired with greater coupling efficiency in calm heifers. Within the LT, integrative PCI+II was greater (P = 0.05) and ECI+II tended to be greater (P = 0.06) in temperamental compared with calm heifers. From 8- to 18-mo old, glutathione peroxidase (GPx) activity decreased (P < 0.0001) and superoxide dismutase activity increased (P = 0.02), and both were similar between muscle groups. The activity of GPx was greater in temperamental compared with calm heifers at 8 (P = 0.004) but not at 12 or 18 mo of age. These results detail divergent skeletal muscle mitochondrial characteristics of live Brahman heifers according to temperament, which should be further investigated as a potential link between temperament and product quality.

Novel genes involved in the genetic architecture of temperament in Brahman cattle

Cattle temperament is a complex and economically relevant trait. The objective of this study was to identify genomic regions and genes associated with cattle temperament. From a Brahman cattle population of 1,370 animals evaluated for temperament traits (Exit velocity-EV, Pen Score-PS, Temperament Score-TS), two groups of temperament-contrasting animals were identified based on their EV-average values ±1/2 standard deviation (SD). To be considered in the calm group, the EV of females ranged between 0.16–1.82 m/s (n = 50) and the EV of males ranged between 0.4–1.56 m/s (n = 48). Females were classified as temperamental if their EV ranged between 3.13–7.66 m/s (n = 46) and males were classified as temperamental if their EV ranged between 3.05–10.83 m/s (n = 45). Selected animals were genotyped using a total of 139,376 SNPs (GGP-HD-150K), evaluated for their association with EV. The Genome-Wide Association analysis (GWAS) identified fourteen SNPs: rs135340276, rs134895560, rs110190635, rs42949831, rs135982573, rs109393235, rs109531929, rs135087545, rs41839733, rs42486577, rs136661522, rs110882543, rs110864071, rs109722627, (P<8.1E-05), nine of them were located on intergenic regions, harboring seventeen genes, of which only ACER3, VRK2, FANCL and SLCO3A1 were considered candidate associated with bovine temperament due to their reported biological functions. Five SNPs were located at introns of the NRXN3, EXOC4, CACNG4 and SLC9A4 genes. The indicated candidate genes are implicated in a wide range of behavioural phenotypes and complex cognitive functions. The association of the fourteen SNPs on bovine temperament traits (EV, PS and TS) was evaluated; all these SNPs were significant for EV; only some were associated with PS and TS. Fourteen SNPs were associated with EV which allowed the identification of twenty-one candidate genes for Brahman temperament. From a functional point of view, the five intronic SNPs identified in this study, are candidates to address control of bovine temperament, further investigation will probe their role in expression of this trait.

Evaluation of dietary trace mineral supplementation in young horses challenged with intra-articular lipopolysaccharide

Sixteen weanling Quarter Horses (255 ± 22 kg) were utilized in a 56-d trial to evaluate the effects of trace mineral (TM) source on intra-articular inflammation following a single acute inflammatory insult. Horses were stratified by age, sex, and BW and then randomly assigned to dietary treatment: concentrate formulated with Zn, Mn, Cu, and Co as inorganic sources (CON; n = 8) or complexed TMs (CTM; n = 8). Added TM were formulated at iso-levels across treatments and intakes met or exceeded NRC requirements. Horses were offered 1.75% BW (as-fed) of treatment concentrate and 0.75% BW (as-fed) coastal Bermudagrass hay. Growth measurements were collected on days 0, 28, and 56, and plasma was collected biweekly for determination of Mn, Cu, Zn, and Co concentrations. On day 42, carpal joints were randomly assigned to receive injections of 0.5 ng lipopolysaccharide (LPS) or sterile lactated Ringer’s solution (LRS; contralateral control). Synovial fluid was collected at preinjection hours (PIH) 0, and 6, 12, 24, 168, and 336 h post-injection and analyzed for TM concentration, prostaglandin E₂ (PGE₂), carboxypeptide of type II collagen (CPII), collagenase cleavage neopeptide (C2C), and aggrecan chondroitin sulfate 846 epitope (CS846). Data were analyzed using the MIXED procedure of SAS. Results showed a TM source × LPS × h effect for synovial fluid Co, Cu, and Se (P < 0.05); concentrations of TM peaked at hour 6 and decreased to preinjection values by hour 168 in both CON and CTM–LPS knees. A delayed peak was observed at hour 12 for CTM–LRS. Peak synovial fluid Cu and Se concentrations were higher in LPS knees, and Co was highest in CTM–LPS. A TM source × h interaction was observed for Zn (P < 0.05); concentrations peaked at hour 6 in CON vs. hour 12 for CTM. An LPS × h interaction was observed for Mn (P < 0.01); synovial concentration peaked at hour 6 in LPS knees compared with hour 24 in LRS. Synovial PGE₂, C2C, CPII, and CS846 concentrations were greater with LPS (P ≤ 0.01), and C2C was greater (P < 0.01) in CTM compared with CON. Concentrations of CPII and PGE₂ were unaffected by diet. A TM source × h × LPS interaction was observed for CS846 (P = 0.02). Concentrations of CS846 in CTM peaked at 12 h, whereas CON peaked at a lower concentration at 24 h (P < 0.05). Data indicate sufficient intake of a complexed TM source may support cartilage metabolism through increased aggrecan synthesis and type II collagen breakdown following an intra-articular LPS challenge in growing horses.

Influence of prenatal transportation stress-induced differential DNA methylation on the physiological control of behavior and stress response in suckling Brahman bull calves

The objective of this experiment was to examine potential differential methylation of DNA as a mechanism for altered behavioral and stress responses in prenatally stressed (PNS) compared with nonprenatally stressed (Control) young bull calves. Mature Brahman cows (n = 48) were transported for 2-h periods at 60 ± 5, 80 ± 5, 100 ± 5, 120 ± 5, and 140 ± 5 d of gestation (Transported group) or maintained as nontransported Controls (n = 48). From the offspring born to Transported and Control cows, a subset of 28-d-old intact bulls (n = 7 PNS; n = 7 Control) were evaluated for methylation of DNA of behavior and stress response-associated genes. Methylation of DNA from white blood cells was assessed via reduced representation bisulfite sequencing methods. Because increased methylation of DNA within gene promoter regions has been associated with decreased transcriptional activity of the corresponding gene, differentially methylated (P ≤ 0.05) CG sites (cytosine followed by a guanine nucleotide) located within promoter regions (n = 1,205) were used to predict (using Ingenuity Pathway Analysis software) alterations to canonical pathways in PNS compared with Control bull calves. Among differentially methylated genes (P ≤ 0.05) related to behavior and the stress response were OPRK1, OPRM1, PENK, POMC, NR3C2, TH, DRD1, DRD5, COMT, HTR6, HTR5A, GABRA4, GABRQ, and GAD2. Among altered (P < 0.05) signaling pathways related to behavior and the stress response were Opioid Signaling, Corticotropin-Releasing Hormone Signaling, Dopamine Receptor Signaling, Dopamine-DARPP32 Feedback in cAMP Signaling, Serotonin Receptor Signaling, and GABA Receptor Signaling. Alterations to behavior and stress response-related genes and canonical pathways supported previously observed elevations in temperament score and serum cortisol through weaning in the larger population of PNS calves from which bulls in this study were derived. Differential methylation of DNA and predicted alterations to behavior and stress response-related pathways in PNS compared with Control bull calves suggest epigenetic programming of behavior and the stress response in utero.

303 Identification of candidate genes related to temperament in Brahman cattle

The objective of this study was to identify genomic regions and genes associated with beef cattle temperament. Temperament, measured as exit velocity (EV; m/s), was recorded in 1,370 Brahman cattle from Texas A&M AgriLife Research at Overton, TX. We identified two groups of temperament-contrasting animals. Cows were calm if their EV of 0.16–3.41 m/s and bulls if their EV was 0.4–3.12 m/s (n-119). Cows were temperamental if their EV was 3.55–7.66 m/s and bulls if their EV was 3.13–10.83 m/s (n = 79). The 198 animals were genotyped using the GGP-HD-150K chip. 139,376 SNPs were evaluated for association with temperament. 13 SNP′s were associated with EV (P &lt; 4.0E-05). The SNPs GABRG2-26484, NRXN3-26436 and TBX20-191081 are located in introns of the GABRG2, NRXN3 and TBX20 genes, respectively. The GABRG2 gene encodes a GABA receptor, the major inhibitory neurotransmitter in the mammalian brain. The NRXN3 gene encodes receptor proteins related to chemical transmission at synapses. TBX20 is a member of the T-box transcription factor family expressed in the developing stages of heart, limbs, eye and ventral neural tube. To test the effect of these 3 SNP′s on EV, Pen-Score and Temperament-Score, a general linear model was fitted including the fixed effects of sex of calf and year of birth, and the individual effect of the 3 SNPs. The marker TBX20-191081 was associated with the three traits evaluated (P &lt; 0.01), where the GG genotype was associated with the calmest temperament. The GG genotype had a significant effect on EV (P &lt; 0.0001) that was 1.35 and 1.95 m/s slower than AG and AA, respectively. For TS, the GG genotype had a TS that was 1.41 and 1.24 DS less than those of the AA and GA genotypes. Our study indicates that genetic control of cattle temperament has a wide network of genes with divergent functions and genetic background specificity.

304 Transgenerational influence of prenatal stress on temperament, birth weight, and weaning weight of Brahman calves

The objective was to evaluate the transgenerational influence of prenatal transportation stress (PNS) on temperament, birth weight, and weaning weight in Brahman calves. Dams were derived from multiparous cows that were transported for 2 h at 60, 80, 100, 120, and 140 d of gestation (n = 48) or maintained as Controls (n = 48). Heifers born to Transported or Control cows were followed through maturity and their calves (n = 79; 35 calves born to Control dams and 44 to PNS dams) studied across multiple years. Calf birth and weaning weights were recorded. Calf temperament at weaning was evaluated utilizing pen score (PS; 1=calm and 5=excitable), exit velocity (EV; m/sec), and temperament score (TS; (PS+EV)/2). Data were analyzed using mixed linear models. Fixed effects included dam treatment, calf sex, and birth season nested within birth year (season nested within year was identified as an efficient parameterization). Calf sire was a random effect. Birth weight was not affected by dam treatment, calf sex, or season nested within year (P &gt; 0.1). Weaning weight was greater in males than females (P &lt; 0.01). Weaning weight was affected by season nested within year (P &lt; 0.01). DOA at weaning was a covariate for weaning weight (0.74±0.09 kg; P &lt; 0.01), but not PS, EV, or TS (P &lt; 0.1). Weaning weight was not affected by dam treatment (P &gt; 0.1). TS was affected by season nested within year (P = 0.04) but not dam treatment or calf sex (P &gt; 0.1). EV was not affected by dam treatment, calf sex, or season nested within year (P &gt; 0.1). PS was affected by season nested within year (P &lt; 0.01) but not calf sex (P &gt; 0.1). Calves born to PNS dams had greater (P = 0.02) PS than calves born to Controls (3.17±0.20 and 2.58±0.22, respectively). There was a transgenerational influence of PNS on temperament but not birth or weaning weight.

376 Awardee Talk - Prenatal transportation stress alters physiology of suckling Brahman calves as mediated by changes in DNA methylation

Mechanisms by which prenatal programming alters the developmental trajectory of biological systems in utero is of relevance to animal agriculture. We hypothesized that prenatally stressed (PNS) calves would exhibit altered postnatal phenotype and differential methylation of DNA. Mature Brahman cows (n = 48) were transported for 2-h periods at 60, 80, 100, 120, and 140 (± 5) d of gestation or maintained as non-transported Controls (n = 48). PNS calves exhibited more excitable temperaments and increased circulating concentrations of cortisol. In response to a glucose tolerance test administered to a subset of PNS and Control bulls, PNS calves returned to basal concentrations of insulin more rapidly and exhibited a lower total area under the insulin response curve. In response to a lipopolysaccharide challenge administered to a subset of PNS and Control bulls, PNS calves exhibited greater circulating concentrations of cortisol and a greater change from baseline for IFN-γ and monocytes. Reduced representation bisulfite sequencing was used to assess methylation of DNA from white blood cells in a subset of 28-d-old bull calves. Because increased methylation of DNA in a gene promoter region typically results in decreased transcriptional activity, differentially methylated CG sites located within promoter regions (n = 1,205) were used to predict alterations to canonical pathways using Ingenuity Pathway Analysis software. There were 113 pathways altered (P ≤ 0.05) in PNS calves. Among these were pathways related to behavior, stress response, metabolism, and immune function. In support of our hypotheses, differential methylation in gene regions related to temperament, stress response, metabolism, and immune response corresponded to phenotypic differences observed in PNS calves, suggesting DNA methylation as a mechanistic basis for prenatal programming. The role of the prenatal epigenome in shaping postnatal outcomes provides novel opportunities to improve animal health and production traits.

PSXIII-13 Comparison of telomere length in age-matched primiparous and multiparous Brahman cows

Telomeres are comprised of G-rich nucleotide sequences (5’-TTAGGG-3’) at the chromosome termini that are responsible for protecting chromosomes; however, attrition of these sequences has been observed in conditions of physiological and psychological stress. The purpose of this study was to compare telomere length (TL) in 4-yr-old Brahman cows grouped by first parity (n = 8) and second parity (n = 11). Cows were bled by jugular venipuncture, weighed, and had BCS recorded d+28 prior to calving and d-7 and d-28 post calving. Cows were observed for duration of labor (Tlabor) and calving ease (CE) at the time of parturition. Calf birth weight (CBW) and gender (CG) were recorded. Peripheral leukocytes were isolated, complete blood counts (CBC) were recorded, and genomic DNA was extracted utilizing silicone membrane spin column kits. The relative quantity of telomere products, which is proportional to the average TL, was determined by multiplex quantitative PCR analysis using the ratio of bovine telomere and β-globulin DNA. An absolute standard of bovine telomere (1012–107 dilution series) and β-globulin (109-104 dilution series) genes was utilized to produce relative copy number. All samples were run in triplicate and samples were included if triplicate Cq difference was less than 0.25 cycles. Parity was the fixed effect of interest and random effects included sire and day repeated with cow as the subject. No differences in CBC were seen. Tlabor, CE, CG, and CBW did not impact TL (P &gt; 0.1). A trend was observed for day-parity interaction (P = 0.0918). TL between parity differed most on d-28 (P = 0.1046; parity one 127292 ± 6483; parity two 111045 ± 5376). The stress of parturition and raising the first calf of a cow’s life may be responsible for slight attenuation in TL.

Skeletal response to whole body vibration and dietary calcium and phosphorus in growing pigs

The quality and strength of the skeleton is regulated by mechanical loading and adequate mineral intake of calcium (Ca) and phosphorus (P). Whole body vibration (WBV) has been shown to elicit adaptive responses in the skeleton, such as increased bone mass and strength. This experiment was designed to determine the effects of WBV and dietary Ca and P on bone microarchitecture and turnover. A total of 26 growing pigs were utilized in a 60-d experiment. Pigs were randomly assigned within group to a 2 × 2 factorial design with dietary Ca and P concentration (low and adequate) as well as WBV. The adequate diet was formulated to meet all nutritional needs according to the NRC recommendations for growing pigs. Low Ca, P diets had 0.16% lower Ca and 0.13% lower P than the adequate diet. Pigs receiving WBV were vibrated 30 min/d, 3 d/wk at a magnitude of 1 to 2 mm and a frequency of 50 Hz. On days 0, 30, and 60, digital radiographs were taken to determine bone mineral content by radiographic bone aluminum equivalency (RBAE) and serum was collected to measure biochemical markers of bone formation (osteocalcin, OC) and bone resorption (carboxy-terminal collagen crosslinks, CTX-I). At day 60, pigs were euthanized and the left third metacarpal bone was excised for detailed analysis by microcomputed tomography (microCT) to measure trabecular microarchitecture and cortical bone geometry. Maximum RBAE values for the medial or lateral cortices were not affected (P > 0.05) by WBV. Pigs fed adequate Ca and P tended (P = 0.10) to have increased RBAE max values for the medial and lateral cortices. WBV pigs had significantly decreased serum CTX-1 concentrations (P = 0.044), whereas animals fed a low Ca and P diet had increased (P < 0.05) OC concentrations. In bone, WBV pigs showed a significantly lower trabecular number (P = 0.002) and increased trabecular separation (P = 0.003), whereas cortical bone parameters were not significantly altered by WBV or diet (P > 0.05). In summary, this study confirmed the normal physiological responses of the skeleton to a low Ca, P diet. Interestingly, although the WBV protocol utilized in this study did not elicit any significant osteogenic response, decreases in CTX-1 in response to WBV may have been an early local adaptive bone response. We interpret these data to suggest that the frequency and amplitude of WBV was likely sufficient to elicit a bone remodeling response, but the duration of the study may not have captured the full extent of an entire bone remodeling cycle.

114 The relationship of cell mediated immune response of Brahman cows on calving interval

The relationships between cell-mediated immune response (CMIR) of cows and calving interval and calf growth were evaluated. Calving interval was evaluated for each of the initial 7 life-time opportunities that females had to produce a calf. The number of days from when the cow had a calf until she calved again determined the cow’s calving interval for each year. The Spring breeding seasons were divided into 45-d artificial insemination and 45-d natural service periods. The Fall breeding season was natural service each year. Multiparous Brahman cows (n = 435) had records for breeding and calving dates and calf weaning weights. The CMIR (hypersensitivity response to Candida albicans measured using tail-fold thickness) was determined once for each female in the Fall and early Winter 2015. Cows were classified into response groups based on mean and SD of CMIR. High responders were those with CMIR ½ SD ≥ the mean (≥ 2.8 mm), Intermediate cows were within ½ SD of the mean (2.7-1.8 mm), and cows ½ SD ≤ the mean were Low (≤ 1.7 mm). Data were analyzed using repeated measures, mixed, and Chi Square procedures (SAS 9.4). Variables included calving interval, cow age, CMIR response group, pregnancy status, calf count, calf sex, cow sire, calf sire, and calf adjusted 180-d weaning weight. A greater proportion of High CMIR cows made it to their 6th calving interval. Chi Square analysis indicated that High CMIR cows were more likely to remain in the herd longer and produce a calf each year. Cows with High CMIR had a greater stayability (P = 0.1). Selection for High CMIR can result in selection of cows which are more likely to remain in the herd long enough to be profitable as they have a greater stayability and shorter calving intervals (about 25 days) than their Low CMIR herdmates.

154 Evaluation of repeated exposure to lipopolysaccharide on vaginal temperature and complete blood count in two-year-old Brahman heifers

The effects of escalating lipopolysaccharide (LPS) doses on vaginal temperature (VT) and complete blood count (CBC) were evaluated to develop a model of low-level inflammatory response in cattle. Brahman heifers (2-yr-old; 326 kg BW) paired by birthdate, sire, and weaning temperament score were fitted with self-contained, indwelling vaginal temperature probes 7 d before initiation of treatment (d 0) and randomly assigned to Control (n = 6) or LPS (n = 6) treatment. Heifers were maintained as a group with free choice access to Coastal bermudagrass hay and fed 3.6 kg of a 3:1 corn:corn gluten grain mix per head per day. Heifers were weighed, BCS recorded, and blood samples were collected weekly by jugular venapuncture before delivery of treatments. Treated heifers received LPS (from Escherichia coli) via subcutaneous injection in the neck (d 0: 0.25 μg / kg BW; d7: 0.50 μg /kg BW; d 14: 0.75 μg /kg BW) and Control heifers received saline. Sickness behavior score (SBS) was monitored at 30-min intervals for 12 hr after LPS. Treatment was the fixed effect of interest. Random effects included sire and day repeated with heifer as the subject. No dose-treatment interactions were detected. The SBS did not change after subcutaneous LPS or saline (P > 0.1). Neutrophil and lymphocyte numbers 7 d after each injection were not affected by LPS (P > 0.1). A febrile response began within 1 hr and persisted up to 14 hr after LPS injections. The febrile effect of the 0.25 μg LPS dose was less pronounced (P < 0.05) than that of the 0.50 μg and 0.75 μg LPS doses which were similar to one another. Lipopolysaccharide treatment increased maximum VT (P < 0.0001), hastened time to attain maximum VT (P = 0.0429), and increased the change in VT (P < 0.0001). Weekly subcutaneous injection of LPS facilitates the study of the effect of sub-clinical illness in beef cattle.

86 Skeletal response to whole body vibration and dietary calcium and phosphorus in growing pigs

Whole body vibration (WBV) is reported to elicit increased bone mass and strength. This experiment was designed to determine the effects of whole body vibration (WBV) and dietary calcium (Ca) and phosphorus (P) on bone microarchitecture and turnover. A total of 26 growing pigs were utilized in a 60-d experiment. Pigs were randomly assigned within group to a 2 × 2 factorial with Ca and P concentration (low and adequate) and WBV. Low Ca, P diets were 0.9 g/kg less than recommended levels of Ca and available P. Pigs receiving WBV were vibrated 30 min/d, 3 d/wk at a magnitude of 1-2mm and frequency of 50 Hz. On d 0, 30, and 60, digital radiographs were taken to determine bone mineral content by radiographic bone aluminum equivalency (RBAE) and blood was collected for bone formation biomarker (osteocalcin, OC) and bone resorption biomarker (carboxy-terminal collagen crosslinks, CTX-I). At d 60, pigs were harvested and the left third metacarpal bone was excised for analysis by micro computed tomography (microCT) to measure trabecular microarchitecture and cortical bone geometry. Maximum RBAE values for the medial or lateral cortices were not affected (P > 0.05) by WBV. Pigs fed adequate Ca and P tended (P = 0.10) to have increased RBAE max values for the medial and lateral cortices. Vibrated pigs had decreased CTX-1 concentrations (P = 0.044). Pigs fed decreased Ca and P had increased (P < 0.05) concentrations of OC. Vibrated pigs had lower trabecular number (P = 0.002) and increased trabecular separation (P = 0.003), whereas cortical bone parameters were not changed by WBV or diet (P > 0.05). Whole body vibration in this study did not elicit an osteogenic response; however, early indications of bone turnover were observed.

Effects of combined viral-bacterial challenge with or without supplementation of Saccharomyces cerevisiae boulardii strain CNCM I-1079 on immune upregulation and DMI in beef heifers

Objectives were to determine whether live yeast (LY) supplementation would affect daily dry matter feed intake, body weight (BW), immune, and febrile responses to a viral-bacterial (VB) respiratory challenge. Crossbred heifers (N = 38, BW = 230 ± 16.4 kg) were allocated into a 2 × 2 factorial treatment arrangement: Factor 1 = roughage-based diet with or without LY (Saccharomyces cerevisiae boulardii CNCM I-1079, 62.5 g/hd/d), Factor 2 = VB, intranasal administration of bovine herpesvirus-1 (BHV-1, 2 ×108, PFU) on day 0 and endobronchial inoculation with Mannheimia haemolytica (5.4 × 1010, CFU) on day 3, or intranasal saline administration followed by inoculation with phosphate buffer solution (PBS). Heifers were fed their respective diets for 27 d prior to VB challenge on day 0. Heifers were housed by treatment and group-fed using electronic feedbunks. Thermo-boluses (Medria; Châteaubourg, FR) measured rumen temperature (RUT) at 5-min intervals and rectal temperature and whole blood samples were collected on days 0, 3 to 8, 10, 13, and 15. Data were analyzed using repeated measures in the mixed procedure of SAS with fixed effects of day, diet, inoculation, and their interactions. Animals fed LY exhibited a 16% increase (P = 0.02) in neutrophils relative to CON. Diet × inoculation × day interactions were detected for monocytes and haptoglobin. The VB-LY had the greatest (P < 0.05) concentration of monocytes on day 4, followed by VB-CON which was greater (P < 0.05) than PBS treatments. Haptoglobin concentration was greatest (P < 0.02) for VB-CON on day 5, followed by VB-LY which was greater (P < 0.05) than PBS. Heifers supplemented with LY had less (P < 0.05) haptoglobin production than CON. The VB challenge produced nasal lesions that increased (P < 0.01) with day, reaching a zenith on day 6 with 70% of the nares covered with plaques, and increased (P < 0.05) neutrophils on days 3 to 5. The VB challenge increased RUT (P < 0.05) days 2 to 7 and rectal temperature (P < 0.05) on days 0 and 3 to 6. The increased rectal temperature on day 0 was likely due to increased ambient temperature at time of challenge, as VB heifers were processed after the PBS heifers to avoid contamination. The VB challenge was effective at stimulating immune responses, and RUT was effective for measuring febrile responses. These results indicate that prior LY supplementation altered the leukogram in response to VB challenge, suggestive of increased innate immune response.